My suggestion is that you were the only one there not bullshitting himself.

And, I'd suggest a better practice, put the sensei, or someone, behind a curtain, and see how people react or don't react based on whether or not the sensei is there, isn't there, or someone else is there. You'll have to keep some tight controls but if you can do that what you'll find is that people suddenly aren't so sensitive afterall. Of course a curtain and the ill intentions of the testers will no doubt damage the ki flow.

I've done similar exercises to the one described, one specifically where you attacked from behind, and were supposed to sense the attack. Interestingly, the room was filled with shadows and mats make noises so there were all kinds of cues to when the attack was happening. Now, I'm all for that kind of sensitivity training (awareness of surroundings and similar) but it wasn't being sold that way. So when I started taking those variables out (attacked towards the sun, attacking quietly, etc) people's performances declined drastically including the sensei's. Well, when that started happening, the teacher made the argument that he was accurately reading my intention to attack...and of course when the person moves the attacker tended to move so basically I needed some big boots to wade through what was being passed around on that mat.

At best people can read someone's intention based on sounds, touch, visual cues and similar things which can produce remarkable and surprising results but it ain't energy shooting out of some sensei's butt.....well, that actually can move people....